1. Field of the Invention PA1 2. Description of the Related Art
The present invention relates to a chemically amplified resist composition and, more particularly, to a photosensitive polymer whose backbone has a cyclic structure and to a resist composition containing the photosensitive polymer for an ArF excimer laser.
As semiconductor devices become highly integrated and complicated to fabricate, fine pattern formation is required. Further, as the capacity of a semiconductor device increases to exceed 1 giga bit, a pattern size having a design rule of less than 0.2 .mu.m is required. Accordingly, there are limitations in using a conventional resist material with a KrF excimer laser (248 nm). Thus, a new resist material capable of being developed using an ArF excimer laser (193 nm) has been developed in a lithography process.
(Meth)acrylate polymers are generally used as the resist material in the lithography process using the ArF excimer laser. However, such polymers have very weak resistance to dry etching. Accordingly, to increase the resistance to dry etching, a polymer having a backbone composed of an alicyclic compound such as an isobornyl group, an adamantyl group or a tricyclodecanyl group, is used. However, the resulting resist still exhibits weak resistance to dry etching.